Trip-free circuit breaker device



, 31, 1968 H- R. SHAFFER I 3,419,838

TRIP-FREE CIRCUIT BREAKER DEVICE FiledDec. 19, 1966 I N VENTOR. #0 1404/90 SAW/ F57? Dec. 31, 1983 H. SHAFFER TRIP-FREE CIRCUIT BREAKER DEVICE Sheet Filed Dec. 19, 1966 H. R. SHAFFER TRIP-FREE CIRCUIT BREAKER DEVICE Dec. 31,1968

Sheet Filed D90- 19, 1966 United States Patent Office 3,419,838 Patented Dec. 31, 1968 ABSTRACT OF THE I)ISCLOSURE A cincuit breaker device which includes a manual operator for moving between the contact ON and contact OFF positions. Movable contact means includes an intermediate connecting member selectively engageable with a reset notch portion of the operating plunger. The connecting member is moved out of the notch as the movable contact makes bridging engagement with the stationary contact means. Under fault condition, the movable contact means can trip open to interrupt the breaker even if the plunger is in its ON condition.

The instant application is an improvement in the type of circuit breaker devices disclosed in US. patent application, filed Sept. 7, 1966, Ser. No. 577,772, now Patent No. 3,379,843, issued Apr. 23, 1968 in the names of myself and Carl E. Gryctko, entitled Circuit Breaker Device, and assigned to the assignee of the instant invention. The circuit breaker devices shown in the aforementioned patent application include a pair of spaced stationary cont-acts which are bridged by a movable contact means to provide an electrically conducted path therebetween. Automatic movement of the movable contact means to its disengaged condition, responsive to a predetermined overload condition, is provided by a bimetallic element which deflects in a manner proportionally related to the current flow therebetween. A manual operating member is provided for purposes of resetting the breaker after the tripping operation thereof (as well as for manually moving the circuit breaker to the OFF condition). Should the circuit breaker be manually closed upon an electrical fault condition, it is extremely desirable that the circuit breaker mechanism be capable of tripping open, irrespective of the condition of or force input to the manual operating member. This is known as trip-free operation, and was not obtainable with the devices shown in the aforementioned patent [application Ser. No. 577,772.

I provide a modification of the previous devices to provide such desirable trip-free operation, while still maintaining a sufficiently simple and low-cost circuit breaker mechanism to be economically feasible in those applications which previously have been restricted to the utilization of replaceable type cartridge fuses.

It is, therefore, seen that a basic concept of my invention resides in the provision of an automatic circuit breaker device of extreme simplicity of operation, compactness of size and low cost which provides trip-free operation.

This advantageous mode of operation is obtained by a unique interconnection between the movable contact means and manually actuated plunger-type operator. More specifically, in the previously disclosed circuit breaker mechanism of application Ser. No. 577,772, there was a permanent connection between the movable contact means, operating spring and manual operating plunger. Thus, should the plunger be downwardly moved for purposes of resetting the breaker, the direct physical connection to the movable contact means would prevent tripping of the breaker, in opposition to a sustained plunger input force, in the event that the breaker is reset upon a fault condition. In accordance with the present invention, the movable contact means includes an intermediate connecting member which is selectively engageable with a reset notch portion of the operating plunger. As soon as the movable contact means makes bridging contact engagement with the stationary contact means, the connecting member is moved out of the plunger notch. Hence, should there be a fault condition, the movable contact means can trip open, to interrupt the breaker, even if the manual operating plunger is forcefully maintained in its ON condition. In order to reset the circuit breaker, means are provided for effecting re-engagement of the plunger notch and the movable contact connecting member upon outward movement of the plunger, such that subsequent inward movement of the plunger will reset the circuit breaker in its ON condition.

In accordance with another advantageous feature of my invention, a trip indicia means is provided to give an external indication that the circuit has been interrupted responsive to an overload condition. Such a trip indicia means is provided in an extremely simple manner by providing a plunger portion which is engaged during tripping movement of the movable contact means, to move the plunger partially outward, such that a visual indication thereon is exposed. It should be noted at this point that the engagement with this plunger portion will not in any way inhibit the separated movement apart of the contacts, or otherwise detract from the trip-free operation of the circuit breaker device.

It is, thus, a primary object of my invention to provide a trip-free circuit breaker device of extreme simplicity of operation and manufacture.

A further object of my invention is to provide a tripfree circuit breaker device, including a manual operating plunger and a novel reset means for providing a selectively disengageable connection between the manual operating plunger and the movable contact means.

Another object of my invention is to provide such a trip-free circuit breaker device which includes indicia means for indicating the trip condition of the circuit breaker.

These as well as other objects of my invention will become readily apparent upon a consideration of the following descriptions and drawings in which:

FIGURE 1 is an exploded perspective view of the circuit breaker device in accordance with my invention, as shown in conjunction with the spring contact clips and mounting base which may typically receive same.

FIGURES 2, 3 and 4 are side elevation, plan and end views of the circuit breaker device of FIGURE 1 shown in its operative condition.

FIGURE 5 is a cross-sectional view along the lines of 55 of FIGURE 4, looking in the directions of the arrows with the mounting block deleted, and showing the circuit breaker in its open condition, and the plunger arm in the reset position.

FIGURE 6 is a cross-sectional view corresponding to FIGURE 5, but showing the circuit breaker during the reset closing operation thereof.

FIGURE 7 shows the circuit breaker device of FIG- URES 5 and 6 in a completely closed condition.

FIGURE 8 shows the circuit breaker device corresponding to an overload condition, in which the bimetallic element has deflected and the circuit breaker is about to trip.

FIGURE 9 shows the circuit breaker device in the trip open condition.

FIGURE 10 shows the circuit breaker device in the course of being moved to the reset condition.

Referring to the figures, circuit breaker device 10 is enclosed within a two-part housing including complementary housing sections 12 and 14. The housing includes an internal volume having first and second side walls 16, 18, respectively, a top wall 20, and a bottom wall 22. First and second stationary contact means 24, 26 are positioned at spaced locations along the bottom wall 22.

Electrically connected to the stationary contact means 24, 26 are external contact means 28, 30, respectively, which are illustratively shown of a generally circular configuration and of a size corresponding to the ferrule ends of commercially available cartridge type fuses. External contact means 28, 30 are integrally formed with a stationary contact means 24, 26, respectively, and tightly engage housing extensions 29, 31. Advantageously, this engagement may serve as the principal retaining means for maintaining complementary housing sections 12, 14 in their abutting relationship, thereby avoiding the necessity of rivets, screws, or similar connecting means. U- shaped arc-chute members 75 are provided having a plurality of openings 77 to expel the gases generated during circuit interruption. Arc chutes 75 concentrate the magnetic flux across the separating contacts, so that any are is extended in length for extinction, and are chute 75 helps cool the arc gases. The arms of the arc chute enter complementary cut outs 79 of the housing sections to serve as a further means for maintaining the complementary housing sections together.

Circuit breaker device may be readily plug-in inserted within conventional type spring contact members 32, 34 mounted to base 36 and having screw-type contacts 38, 40 for receiving the leads (not shown) to the external circuit being protected by the circuit breaker 10.

Circuit breaker stationary contact pair 24, 26 are of the bridging variety; that is, when an electrically conductive path is provided therebetween, a circuit will be provided through the circuit breaker device 10 intermediate external contact means 28-30. This bridging type contact is provided by the combined movable contact means 50, which is a bimetallic element, and includes contact elements 54, 56 at its opposite ends.

A manual operator, or plunger 60, is positioned within housing seating means 80, for reciprocal movement, towards and away from stationary contacts 24-26, as will henceforth be described. In accordance with my invention, a selectively disengageable connection between the plunger 60 and the movable contact means is provided by a connecting means including plunger notch 62 and intermediate connecting member 70.

The connecting member 70 includes a first portion 72 secured to the central portion of bimetallic element 50, as by spot welding or brazing; a second portion 76 connected to the operating spring 92; and a third portion 74 which engages the plunger notch opening 62.

Operating spring member 92 is mounted with its opposed ends 94, 96 within notched recesses 95, 97 of the housing side walls 16, 18. These notches seat spring member 92 and restrain it against longitudinal movement. The central portion of the spring member enters slotted opening 76, to provide an operative connection to the movable contact means 50. Spring member 92 is of a length greater than the distance between side wall notches 95, 97, and hence will are about its centerline 100 between opposed overcenter positions, as shown in FIGURES 7 and 9, respectively. As discussed in aforementioned US. patent application Ser. No. 577,772, the movement of the spring member between such opposed overcenter positions is a snap action so as to provide rapid engagement and disengagement between movable contact elements 54, 56 and its stationary contact means 24, 26.

The housing further includes extending portion 45 which engages the left end of the movable contact means 50, in the manner sequentially shown in FIGURES 10 and 5, to provide engagement between plunger notch 62 and end portion 74 of connecting member 70, during the resetting of the circuit breaker mechanism.

Plunger 60 is further shown including projecting portion 63, which may typically be a pin, which is engaged by the upward movement of movable contact member 50 for purposes of providing an external indication of tripping. That is, such upward movement of the plunger exposes indicator means 65 of the plunger, which may typically be a colored stripe. (See FIGURE 9.) Plunger 60 also includes a manual disengage operator 66, which engages the underside of 50 to provide disengagement of the circuit breaker responsive to upward movement of the plunger.

Considering now the operation of my circuit breaker device, reference is made to FIGURE 5, which shows the circuit breaker in the reset position. Operating plunger 60 has been manually moved to its outward extreme, such that end region 74 of connecting member 70 is located in notched opening 62 of the plunger. This reset engagement between 62 and 74 is provided by the upward force of spring member 92 on member 50, with its upward movement on the left side being limited by the engagement thereof with housing reset extension 45.

FIGURE 6 shows the manner in which the circuit breaker is reset closed by continued downward movement of plunger 60, in the direction shown by the arrow 110. Inasmuch as reset portion 74 of the connecting member 70 is located in the plunger notched recess 62, such downward movement of the plunger is accompanied by downward movement of both the movable contact member 50 and operating spring 92, which, it will be recalled, is located in recessed opening 76 of the connection member. As shown in FIGURE 6, movable contact element 54 has engaged stationary contacts 24 and spring member 92 is about to go overcenter. Continued downward movement of plunger 60 causes the spring to go overcenter, to the completely closed position shown in FIGURE 7. Movable contact 56 engages stationary contact 26, and firm contact engagement between the movable and stationary contact means is provided by the force of spring 92. -It is to be specifically noted at this point that as the spring goes overcenter from the position shown in FIGURE 6 to that shown in FIGURE 7, with the force of the spring moving the contacts to their final engaged position, portion 74 of connecting member 70 moves out of plunger notch 62. Thus, the connection between movable contact 50 and operating spring 92 is still maintained by the connecting member 70, but this operating assembly is now disconnected from plunger 60. Hence, should the breaker be closed on a fault, and a continual manual force be provided in the direction of arrow 110, the breaker will still be free to trip open.

Should it be desired to manually move the circuit breaker to the OFF condition from that shown in FIG- URE 7, it is merely necessary to move plunger 60 upwardly, as shown by arrow 115, such that manual disengage operator 66 of the plunger engages the underside of the bimetallic actuator 50, thereby moving it upward.

FIGURE 8 shows the initiation of circuit breaker tripping responsive to a predetermined sustained current flow through bimetallic element 50. The bimetal 50 will begin to distortively deflect, as shown in this figure, with such upward movement being transmitted to the central portion of operating spring 92 via connecting means 76. When the point is reached that the spring 92 moves past its overcenter position, there will be rapid, snap-action in the manner analogous to an overcenter toggle structure, such that there is rapid disengagement of the contacts to the trip condition shown in FIGURE 9. As the breaker moves to the trip position of FIGURE 9, the central portion of the movable contact means 50 engages pin 63 of the plunger, thereby moving the plunger 60 upward a predetermined extent sufficient to expose indicia means 65, carried by the plunger. This serves to provide an externally perceptible indication of circuit breaker tripping.

The breaker will then remain in the disengaged trip condition of FIGURE 9 until manual reset. Such manual reset is effected by first moving the plunger outward as shown in FIGURE 10, until end portion 74 of connection member 70 is located in plunger recess 62 shown in FIGURE 5, with the plunger then being moved downward, as discussed above in conjunction with FIGURE 6.

It is, therefore, seen that my invention provides a tripfreecircuit "breaker device of extreme simplicity of operation and construction, wherein the trip free operation is provided by a novel interconnection between the manually operating plunger and movable contact means.

Although I have described preferred embodiments of my novel invention, many variations and modifications will now be obvious to those skilled in the art, and I prefer therefore to be limited not by the specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows.

I claim:

1. A circuit breaker comprising:

a housing having an internal volume including first and second sidewalls, a topwall and a bottom wall;

first and second stationary contact means positioned at spaced locations along said bottom wall;

circuit breaker operating means including:

a movable contact means for electrically bridging between said first and second stationary contact means;

a plunger mounted in housing seating means for reciprocal translation along a path towards and away from said bottom wall;

said plunger including a manual operator at one end thereof extending outward of said housing and a reset portion located along the intermediate length thereof, translatable within said internal volume;

a spring member having first and second ends mounted to said first and second sidewalls;

first connecting means for operatively connecting said movable contact means to an intermediate region of said spring member;

second connecting means for providing a selectively disengageable connection between said plunger reset portion and said movable contact means;

said spring member having first and second operative positions, in opposed overcenter relationships with respect to its end locations; said first operative position corresponding to said intermediate region of the spring positioned between said spring ends and said bottom wall such that said intermediate region is downwardly arced for moving said first connecting means downward, and said movable contact means in contact bridging engagement with said stationary contact means so as to provide an electrically conductive path therebetween;

said second operative position corresponding to said intermediate region of the spring positioned between said spring ends and said topwall, such that said intermediate region is upwardly arced for moving said first connecting means upward, and said movable contact means in disengagement with respect to said stationary contact means so as to interrupt said electrically conductive path;

said movable contact means including an elongated bimetallic element for deflection responsive to a predetermined current flow therethrough; said first connecting means operatively transmitting said bimetallic element deflection to said spring member; for moving said spring member between its first and second operative positions responsive to a predetermined amount of bimetallic element deflection;

said second connecting means providing engagement between said movable contact means and said plunger reset portion at a reset plunger position corresponding to said circuit breaker movable contact means being in its disengaged condition;

said seating means mounting said plunger for guided downward movement to return the overcenter relationship of said spring member into said first operative position;

said second connecting means operatively constructed to provide disengagement of said plunger reset portion and movable contact means corresponding to said circuit breaker being returned to said first operative position, whereby the subsequent movement of said circuit breaker into said second operative position, responsive to deflective movement of said bimetallic element, is independent of a sustained downward force input to said manual operator.

2. A circuit breaker as set forth in claim 1:

said plunger including a manual operator at one end thereof extending outward of said housing, and a reset portion located along the intermediate length thereof, translatable within said internal volume;

said second connecting means and manual operator operatively related to initiate engagement with said movable contact means upon manual movement of said manual operator to said reset plunger position.

3. A circuit breaker as set forth in claim 2:

said plunger further including a manual disengage operator;

said manual disengage operator located along said plunger, such that upward movement of said lunger manual operator, when said circuit breaker is in said first operative position, connecting said manual disengage operator to the intermediate region of said movable contact means for upward movement thereof to a said second operative position.

4. A circuit breaker as set forth in claim 1:

further including trip indicia means for providing an indication, external of said housing, that said bimetallic element has deflected and moved said spring member to said second operative position.

5. A circuit breaker as set forth in claim 4:

said trip indicia means including a portion of said plunger in the path of upward movement of said movable contact means, and a visual indicator on said plunger, located inwardly adjacent said one manual operator end for movement out of said housing responsive to movement of said movable contact means to said second operative position.

6. In a circuit breaker as set forth in claim 1:

said second connecting means including a notch along the intermediate length of said plunger; and an extending portion of said movable contact means adapted to enter said notch responsive to outward movement of said plunger manual operator to its reset position.

7. In a circuit breaker as set forth in claim 1:

said movable contact means including a connecting member having first, second and third portions;

said first portion secured to said bimetallic element;

said first connecting means including said second portion;

said second connecting means including said third portion.

8. In a circuit breaker as set forth in claim 7:

said second connecting means further including a notch along the intermediate length of said plunger adapted to selectively engage said third portion.

References Cited UNITED STATES PATENTS GEORGE HARRIS, Primary Examiner.

HIRAM B. GILSON, Assistant Examiner.

US. Cl. X.R. 

